In a conventional chain saw, a hand guard for protecting operator's hands is provided in front of a handle. Additionally, a brake band is wound around a brake drum which also serves as a centrifugal clutch drum, for stopping the operation of a cutting chain. By operating the hand guard and pulling one end of the brake band, the brake drum is tightened with the brake band, thereby stopping the fitting chain.
However, in such chain saw, even after a trigger switch for supplying power to a motor is turned off, the inertial rotation of the motor often results in the rotation of the cutting chain for several seconds. If the rotating chain contacts or hits the ground, it often damages, thereby requiring the replacement of the chain itself. Furthermore, the operator cannot go to the subsequent steps of work until the chain is completely stopped. Thus, the work efficiency is deteriorated.